The use of sidepocket mandrels and fluid control valves, such as gas lift valves, is old. However, in many cases there is a need for increasing the volume of gas admitted by the valves which is needed for lifting purposes. The exterior dimensions of mandrels are limited, and therefore the size of the valves, which may be installed therein, is similarly limited. One way of increasing gas flow is the use of a multiple valve pocket mandrel and valves such as shown in U.S. Pat. No. 3,874,445, but such installation requires multiple down hole trips for installing or removing the individual valves and multiple locks.
The present invention is directed to an improved mandrel and improved flow control valves in which vertically connected multiple flow control valves are placed in the sidepocket of a mandrel thereby increasing the capacity of the mandrel but allowing a single down well trip to be made to install or remove the multiple valves and in addition requiring only a single lock for the latching multiple valves in the sidepocket.